Electro-optical deflection apparatus using holographic grating

Abstract

An apparatus for deflecting beams of radiated energy, for example, laser beams, includes a primary deflector capable of deviating the incident beams into a plurality of directions, e.g., under the control of an electric field or by other means. In order to amplify the angular deflection so obtained, a set of essentially parallel diffraction gratings intercepts the deviated beams. The grating parameters are so chosen that each of the incident beams, arriving at slightly different incident angles, is diffracted by at least one grating in the set of diffraction gratings. Since the diffraction angle is substantially larger than the incident angle, an effective amplification of the angular deflection results. The apparatus is adaptable to deflection in a plane and may be used for storing information in holograms.

What is claimed is: 
     
       1. Apparatus for deflecting an incident beam of radiated energy under the control of an incoming electrical signal, said apparatus comprising: a radiated energy beam deviator capable of deviating, under the control of said incoming electrical signal, said incident beam of radiated energy into a deviated beam having one of a plurality of first different angular directions; and   a plurality of LIPPMANN-BRAGG holographic diffraction gratings disposed and located so as to successively intercept said deviated beam arriving from said beam deviator, one of said gratings causing a diffraction of said deviated beam having one of said first different angular directions into a largely deviated output beam having one of a plurality of second different larger angular directions, the other of said gratings merely transmitting said deviated beam having said one direction, and each of said gratings corresponding to one of said first angular directions and to one of said second angular directions; whereby the value of the angular deflection of the beam is increased.   
     
     
       2. An apparatus as defined in claim 1, wherein the surfaces of the diffraction gratings in said plurality of diffraction gratings are mutually parallel. 
     
     
       3. An apparatus as defined in claim 1, wherein the individual diffraction gratings in said plurality of diffraction gratings all have the same index of refraction, and wherein said plurality of diffraction gratings is immersed in a medium having the same index of refraction as said diffraction gratings. 
     
     
       4. An apparatus as defined in claim 1, wherein said plurality of diffraction gratings is contained within the same single material. 
     
     
       5. An apparatus for deflecting an incident beam of radiated energy under the control of a first and a second incoming electrical signals, said apparatus comprising: a first radiated energy beam deviator capable of deviating, under the control of said first incoming electrical signal, said incident beam of radiated energy into a first deviated beam having one of a plurality of first different angular directions lying in a first deviation plane;   a plurality of first LIPPMANN-BRAGG holographic diffraction gratings disposed and located so as to successively intercept said first deviated beam arriving from said first beam deviator, one of said first gratings causing a diffraction of said first deviated beam having one of said first different angular directions into a largely deviated second beam having one of a plurality of second different angular directions lying in said first plane, the other of said first gratings merely transmitting said first deviated beam having said one of said first directions, and each of said first gratings corresponding to one of said first angular directions and to one of said second angular directions;   a second radiated energy beam deviator, positioned for receiving from said first diffraction gratings said second beam, and capable of deviating, under the control of said second incoming electrical signal, said second beam into a third deviated beam having one of a plurality of third different angular directions lying in a second deviation plane at an angle with said first deviation plane; and   a plurality of second LIPPMANN-BRAGG holographic gratings, disposed and located so as to successively intercept said third deviated beam arriving from said second beam deviator, one of said second gratings causing a diffraction of said third deviated beam having one of said third different angular directions into a largely deviated fourth beam having one of a plurality of fourth different larger angular directions lying in said second plane, the other of said second gratings merely transmitting said third deviated beam having said one of said third directions, and each of said second gratings corresponding to one of said third angular directions and to one of said fourth angular directions.   
     
     
       6. An apparatus as defined in claim 5, wherein said first beam deviator and said second beam deviator are acousto-optical beam deviators. 
     
     
       7. An apparatus as defined in claim 1, wherein said beam deviator is an acousto-optical beam deviator. 
     
     
       8. An apparatus for storing information data, which comprises: means for providing, under the control of an incoming electrical data signal, an incident beam of radiated energy;   a first radiated energy beam deviator capable of deviating, under the control of a first incoming electrical signal, said incident beam of radiated energy into a first deviated beam having one of a plurality of first different angular directions lying in a first geometric plane;   a plurality of first LIPPMANN-BRAGG holographic diffraction gratings disposed and located so as to successively intercept said first deviated beam arriving from said first beam deviator, one of said first gratings causing a diffraction of said first deviated beam having one of said first different angular directions into a largely deviated second beam having one of a plurality of second different angular directions lying in said first plane, the other of said first gratings merely transmitting said first deviated beam having said one of said first directions, and each of said gratings corresponding to one of said first angular directions and to one of said second angular directions;   a second radiated energy beam deviator, positioned for receiving from said first diffraction gratings said second beam, and capable of deviating, under the control of a second incoming electrical signal, said second beam into a third deviated beam having one of a plurality of third different angular directions lying in a second deviation plane at an angle with said first deviation plane; and   a plurality of second LIPPMANN-BRAGG holographic gratings, disposed and located so as to successively intercept said third deviated beam arriving from said second beam deviator one of said second gratings causing a diffraction of said third deviated beam having one of said third different angular directions into a largely deviated fourth beam having one of a plurality of fourth different larger directions lying in said second plane, the other of said second gratings merely transmitting said third deviated beam having said one of said third directions, and each of said second gratings corresponding to one of said third angular directions and to one of said fourth angular directions;   information storage means, disposed to intercept said fourth beam; whereby said fourth beam writes said information data in said information storage means.